Engine control systems and methods

ABSTRACT

A system comprising an air actuator configured to control air delivered to an engine; a fuel actuator configured to control fuel delivered to an engine; and a controller configured to: actuate the air actuator in response to a first torque signal; and actuate the fuel actuator in response to a second torque signal.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/628,552 filed on Feb. 23, 2015, which is a continuation ofInternational Application No. PCT/US2013/056302 filed on Aug. 22, 2013,which claims priority to, and is a continuation-in-part of, U.S. patentapplication Ser. No. 13/591,590 entitled “ENGINE CONTROL SYSTEMS ANDMETHODS” and filed on Aug. 22, 2012, and now issued as U.S. Pat. No.9,115,664 on Aug. 25, 2015, each of which is incorporated herein byreference in its entirety for all purposes.

BACKGROUND

The technical field generally relates to engine control systemsdiagnostics and, in particular, to engine control systems using torqueactuation.

Spark ignited (SI) engines can be controlled differently thancompression ignited (CI) engines. For example, SI engines typicallyattempt to maintain a stoichiometric air to fuel ratio (AFR). Torquefrom an SI engine is primarily controlled through control of air. Incontrast, the AFR for CI engines can vary from the stoichiometric AFR.Accordingly, fuel can be controlled independent of air, introducing acontrol not available on homogenous charge SI engines. Furthermore,gasoline direct injection (GDI) SI engines can be operated withstratified charges, i.e. with varying AFR. Thus, the control of torquecan vary based on engine structure.

Therefore, further technological developments are desirable in thisarea.

SUMMARY

One embodiment is a unique system comprising an air actuator configuredto control air delivered to an engine; a fuel actuator configured tocontrol fuel delivered to an engine; and a controller configured to:actuate the air actuator in response to a first torque signal; andactuate the fuel actuator in response to a second torque signal.

Other embodiments include unique methods and systems to control enginesof different types. Further embodiments, forms, objects, features,advantages, aspects, and benefits shall become apparent from thefollowing description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a torque based engine control systemaccording to an embodiment.

FIG. 2 is a block diagram of an example of an air control systemaccording to an embodiment.

FIG. 3 is a block diagram of another example of an air control systemaccording to an embodiment.

FIG. 4 is a block diagram of an example of a fuel control systemaccording to an embodiment.

FIG. 5 is a block diagram of another example of a fuel control systemaccording to an embodiment.

FIG. 6 is a block diagram of a spark control system according to anembodiment.

FIG. 7 is a block diagram of a torque based engine control systemaccording to an embodiment.

FIG. 8 is a block diagram of a vehicle with an engine system accordingto an embodiment.

FIG. 9 is a schematic depiction of a controller utilizing multipletorque control schemes.

DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended, any alterations and further modificationsin the illustrated embodiments, and any further applications of theprinciples of the invention as illustrated therein as would normallyoccur to one skilled in the art to which the invention relates arecontemplated herein.

In an embodiment, engine systems having different architectures can becontrolled by a common torque control technique. That is, a commontechnique can be applied to spark ignited (SI) engines, gasoline directinjection (GDI) engines, compression ignited (CI) engines, or othersimilar engines based on fuel and air. As will be described in furtherdetail below, in an embodiment, a torque based interface can provide atransformation from the torque input to appropriate fuel, air, and otherparameters for a particular engine architecture.

The controls, systems, and procedures described herein allow a singlecontrol scheme to control engine torque for a stoichiometric engineand/or for a lean burning engine, either within the same engine atdifferent operating times or for distinct engines with only acalibration difference between the engines rather than a fundamentalcontroller difference.

Certain elements described herein are depicted and/or presented as acontroller or controller element. A controller forms a portion of aprocessing subsystem including one or more computing devices havingmemory, processing, and communication hardware. The controller may be asingle device or a distributed device, and the functions of thecontroller may be performed by hardware and/or as computer instructionson a non-transient computer readable storage medium.

In certain embodiments, a controller includes one or more modules,and/or one or more separately described control elements. The modulesand/or separately described control elements are structured tofunctionally execute the operations of the controller. The descriptionherein including modules and/or individually described control elementsemphasizes the structural independence of the aspects of the controller,and illustrates one grouping of operations and responsibilities of thecontroller. Other groupings that execute similar overall operations areunderstood within the scope of the present application. Modules and/orcontrol elements may be implemented in hardware and/or as computerinstructions on a non-transient computer readable storage medium.Modules and/or control elements may be distributed across varioushardware or computer based components.

Example and non-limiting module or controller elements implementationexamples include sensors providing any value determined herein, sensorsproviding any value that is a precursor to a value determined herein,datalink and/or network hardware including communication chips,oscillating crystals, communication links, cables, twisted pair wiring,coaxial wiring, shielded wiring, transmitters, receivers, and/ortransceivers, logic circuits, hard-wired logic circuits, reconfigurablelogic circuits in a particular non-transient state configured accordingto the module or control element specification, any actuator includingat least an electrical, hydraulic, or pneumatic actuator, a solenoid, anop-amp, analog control elements (springs, filters, integrators, adders,dividers, gain elements), and/or digital control elements.

Certain operations described herein include operations to interpret oneor more parameters. Interpreting, as utilized herein, includes receivingvalues by any method known in the art, including at least receivingvalues from a datalink or network communication, receiving an electronicsignal (e.g. a voltage, frequency, current, or PWM signal) indicative ofthe value, receiving a computer generated parameter indicative of thevalue, reading the value from a memory location on a non-transientcomputer readable storage medium, receiving the value as a run-timeparameter by any means known in the art, and/or by receiving a value bywhich the interpreted parameter can be calculated, and/or by referencinga default value that is interpreted to be the parameter value.

Where values are described explicitly or implicitly as input elements toa controller, the values may be determined by any method understood inthe art. Input values may be taken from sensor values, calculated fromsensor values, and/or provided to the system as readable values storedon a non-transient computer readable medium. In certain embodiments, avalue may be determined from a virtual sensor or other calculation basedon other values. In certain embodiments, the source of a given value mayvary with time, for example and not limited to value sources changing inresponse to system conditions, a sensor or other fault occurrence, areliability estimate of a value, or any other control managementoperation as will be understood in the art.

FIG. 1 is a block diagram of a torque based engine control systemaccording to an embodiment. In this embodiment the engine control system10 includes a controller 11. The controller is configured to provide aircontrol 12, fuel control 14, and spark control 16. The controls 12, 14,and 16 can be responsive to one or more torque inputs 18.

The controller 11 can be coupled to various actuators. An air actuator26, a fuel actuator 28, and a spark actuator 30 are illustrated.However, other actuators can be present.

The air control 12 can be configured to generate an air control signal20. The air actuator 26 can be configured to control delivery of air toan engine in response to the air control signal 20. For example, the airactuator 26 can be an electronic throttle. Any device coupled to acompressor, throttle, intake manifold, or the like can be the airactuator 26 or part of the air actuator 26, and can be responsive to theair control signal 20.

Similarly, the fuel control 14 can be configured to generate a fuelcontrol signal 22. The fuel actuator 28 can be configured to controldelivery of fuel to the engine in response to the fuel control signal22. For example, the fuel actuator 28 can include fuel injectors, fuelpumps, other fuel system components, or the like.

The spark actuator 30 can be configured to control ignition in an enginein response to the spark control signal 24. For example, the sparkactuator 30 can be an electronic ignition system configured to actuatespark plugs. Although spark plugs as part of a spark actuator 30 as beenused as an example, any device that can affect a timing, sequence, orthe like of an ignition can be part of the spark actuator 30 and can beresponsive to the spark control signal 24.

The spark actuator 30 is illustrated in phantom. In particular, thespark actuator 30 can be present in an SI engine. However, a sparkactuator 30 may not be present in a CI engine. In an embodiment, thespark control 16 functionality can still be present in the controller 11for a CI engine, yet a connection to a spark actuator 30 is not made asit is not present for the CI engine. That is, the same controller 11and/or functionality implemented by the controller can be used betweenSI and CI engines.

In an embodiment, the controller 11 can be configured to respond to avariety of torque inputs 18. For example, the torque inputs 18 canrepresent an instantaneous torque and a longer-term torque. Theinstantaneous torque can be a desired torque on a time scale of acylinder event, such as a power stroke of a piston, a complete cycle ofa cylinder, or the like.

The longer-term torque can represent a desired torque over a longer timescale. For example, a threshold for a longer-term torque can includemultiple cylinder cycles. In an embodiment, the number of cycles can beon the order of a number of cylinders of an engine, such as 4, 6, 8, 10,12, or the like. In another embodiment, the division betweeninstantaneous torque and longer-term torque can be substantiallyindependent of cylinder cycles. For example, the division can be basedon a propagation delay time for an air control system including the airactuator 26.

In an embodiment, torque generated in response to an air actuator 26 canhave a slower response than torque generated by a fuel actuator 28.Accordingly, two torque signals can be used. As will be described infurther detail below, an air actuator can be actuated in response to afirst torque signal and a fuel actuator can be actuated in response to asecond torque signal. The longer-term torque signal and theinstantaneous torque signal can be the first and second torque signals.That is, the air actuator can be actuated in response to the longer-termtorque signal and the fuel actuator can be actuated in response to theinstantaneous torque signal; however, in other embodiments, the variousactuators 26, 28, and 30 can be responsive to different torque signals,combinations of such torque signals, or the like.

The torque signals 18 can be generated from a variety of sources. Forexample, longer-term torque signals can be generated by a user, acruise-control system, an idle-control system, or the like. Any systemthat may change on a time scale on the order of or greater than aresponse time of an air control system can provide part or the entirelonger-term torque signal. Similarly, control systems that change at afaster rate, such as a transmission control system, or the like, cancontribute to the instantaneous torque signal. Although a responsivenessof an air control system has been used as a threshold, a divisionbetween contributors to the torque signals can be selected as desired toapportion contributions to the air control 12, fuel control 14, sparkcontrol 16, or the like.

Furthermore, any number of torque inputs 18 can be used. For example,each of the air actuator 26, fuel actuator 28, and spark actuator 30,can be configured to have different response times. Each could have adifferent associated torque input 18.

FIG. 2 is a block diagram of an example of an air control systemaccording to an embodiment. In this embodiment, the air control 40includes a torque to fuel conversion 42. The torque to fuel conversion42 can be configured to convert a torque input 44 into a fuel signal 48.Other signals can be input to the torque to fuel conversion 42. In thisembodiment, a spark signal 46 can be input to the torque to fuelconversion 42. The spark signal 46 can be an optimum spark signal, suchas a maximum braking torque. In response, the torque to fuel conversion42 can convert the torque signal 44 and spark signal 46 to the fuelsignal 48. In an embodiment, the torque signal 44 can be the longer-termtorque signal described above.

The fuel signal 48 can be multiplied with an AFR 52 in multiplier 50 togenerate an air signal 54. AFR limits 56, such as emissions limits,operational limits, or the like, can be applied by limiter 56. Forexample, for a CI engine, a lower limit can be related to a smoke limitand an upper limit can be related to nitrogen oxide emissions. Inanother example, the AFR limit can be related to a stoichiometric AFR orother target AFR of an SI engine. Accordingly, the air signal 54 can belimited by such limits to generate the air control signal 60. The aircontrol signal 60 is an example of the air control signal 20 describedabove.

As described above, different limits and/or sets of limits can be usedon different engine types. That is, a CI engine can have an upper andlower AFR limit while an SI engine can have a stoichiometric or singletarget AFR limit. This change can reflect a difference between an SIengine and a CI engine. Thus, the control system can be applied withdifferent engine types with such a parameter change while the underlyingsoftware, firmware, or the like need not change.

FIG. 3 is a block diagram of another example of an air control systemaccording to an embodiment. In this embodiment, the air control 70includes a torque to air converter 72. The torque to air converter 72 isconfigured to convert a torque signal 74, a spark signal 76, and an AFRlimit signal 78 into an air signal 80. For example, a longer-term torquesignal and an optimal spark signal can be converted into an intermediateair signal. The air signal can be limited by a lower limit AFR signal togenerate the air signal 80. That is, an amount of air for a desiredtorque can be determined then limited by a lower AFR limit, for examplea smoke limit.

The maximum 82 of the air signal 80 and a second air signal 84 can beused to generate air signal 86. The air signal 84 can be an input fromother control systems, such as the fuel control 14, spark control 16, orthe like. Accordingly, a longer-term normally lean mode of operation canbe used. That is, a maximum of the desired air can be used so thatadditional margin can be present to operate the engine with a richerAFR, potentially without increasing the amount of air supplied to acylinder.

The maximum air signal 86 can be used as the air control signal 20described above to actuate the air actuator 26. However, in otherembodiments, the maximum air signal 86 can be limited by AFR limits asin FIG. 2, such as by an upper AFR limit, or the like.

FIG. 4 is a block diagram of an example of a fuel control systemaccording to an embodiment. In this embodiment, the fuel control 100includes a torque to fuel converter 102. The torque to fuel converter102 is configured to convert a torque signal 104 and a spark signal 106into a fuel signal 108.

In particular, the fuel signal 108 can be a second fuel signal if usedin conjunction with the air control 40 described above. Furthermore, thetorque signal 104 can be an instantaneous torque signal as describedabove. That is, control signals of the fuel control 100 can be based ona different torque signal than the air control 40.

The fuel control signal 108 can be limited by limiter 110. The limitscan be AFR limits 112. In an embodiment, the AFR limits 112 for the fuelcan be formed from an AFR limit in an air-to-fuel ratio format and anestimated air signal. For example, for a given cycle of the fuel control100, an estimated amount of air can be divided by one or moreair-to-fuel ratios to generate the AFR limits 112 for the fuel signal108. Accordingly, a limited fuel signal 114 can be generated. Similar tothe air control 40 described above, the AFR limits 112 can be selectedas appropriate to the type of engine.

The limited fuel signal 114 can be used as a setpoint for an AFR controlloop. For example, an AFR feedback system 118 can provide feedback froman oxygen sensor. This can be combined appropriately in adder 116 togenerate fuel control signal 120. The fuel control signal 120 can beused as the fuel control signal 22 described above.

FIG. 5 is a block diagram of another example of a fuel control systemaccording to an embodiment. In this embodiment, the fuel control 130includes a torque to air converter 132. Similar to the torque to airconverter 72, the torque to air converter 132 can be configured toconvert a torque input 134, and a spark input 136 to an air signal 140.However, the torque to air converter 132 can also be configured togenerate the air signal 140 in response to an AFR input 138. Forexample, the torque input 132 can be the instantaneous torque and thespark input 136 can be an optimal spark timing. In addition, the AFRinput 138 can be a target AFR signal.

A maximum 142 of the air signal 140 and another air signal 144, such asan air signal 80 described above, can generate a maximum air signal 146.The maximum air signal 146 can be divided in 148 by the target AFRsignal 138 to generate a fuel signal 150. The fuel signal 150 can belimited by limiter 152 and AFR limits 154 similar to FIG. 3 to generatea limited fuel signal 156. In addition, the limited fuel signal 156 canbe an input to an AFR control system with AFR feedback 160 and adder 158to generate the fuel control signal 162. The fuel control signal 162 canbe used as the fuel control signal 22 described above.

Although various torque to fuel converters and torque to air convertershave been described above using air-based signals or fuel-based signal,the character of the control signals can be implemented as desired. Forexample, the air control 20 can use air-based control signals while thefuel control 22 uses fuel-based control signals, or vice-versa.

FIG. 6 is a block diagram of a spark control system according to anembodiment. In this embodiment, the spark control 180 can be configuredto generate a spark control signal 190 in response to a fuel signal 184,torque signals 186 and 187, and a spark signal 188. For example, thefuel signal 184 can be a fuel signal 115, 156, or the like describedabove. The torque signals 186 and 187 can be the instantaneous torqueand longer-term torque described above. From these signals, a sparkcontrol signal 190 can be generated.

Although a spark signal 188 has been described as an input, some enginesmay not use a spark input. For example, a CI engine may not have a sparkinput, let alone an optimal spark. Accordingly, such inputs can beignored, may not be present, or the like when the control system isconfigured for a CI engine.

FIG. 7 is a block diagram of a torque based engine control systemaccording to an embodiment. In this embodiment, the engine controlsystem 200 can include a controller 201 similar to controller 11described above. That is, the controller 201 can include torque inputs218, an air control 212, a fuel control 214, a spark control 216, and beconfigured to generate the associated control signals 220, 222, and 224for actuators 226, 228, and 230.

However, the controller 201 can include a memory 202 configured to storea parameter 204. Although illustrated as part of the controller 201, thememory 202 can be separate from the controller 201, distributed betweenthe controller 201 and external systems or the like. Furthermore, thememory 202 can be configured to store other code and/or data associatedwith the controller 201 or other control systems.

The controller 201 can be configured to control air and fuel deliveredto an engine in response to the parameter 204. In particular, the enginecan be controlled in a stoichiometric mode when the parameter has afirst value and a lean mode when the parameter has a second value.

In particular, the parameter 204 can represent various aspects of thecontrol system that can differ between CI and SI engines. As describedabove, CI engines and SI engines can have different AFR limits. The AFRlimits are examples of the parameter. That is, if upper and lower AFRlimits are substantially equal, the engine can be controlled in astoichiometric mode and if the upper and lower AFR limits are unequal,the engine can be controlled in a lean mode.

Other parameters of the control system that can be the parameter 204 caninclude torque models used for the various torque to air or fuelconverters and spark controls described above. That is, particulartorque models can be used for an SI engine while different torque modelscan be used for a CI engine. A given torque model can be loaded into thememory 204 and cause the controller 201 to operate in a stoichiometricmode, a lean mode, or the like.

Although various types of parameters have been used as examples of theparameter 204, the parameter can be an abstract parameter. For example,the parameter 204 can be a flag, bit, register, or the like that can beset to indicate an operational mode. That is, once the parameter 204 isset, appropriate AFR limits, torque models, or the like can be selectedand used during operation of the engine. As a result, common software,firmware, or the like can be used among multiple engine types bychanging configurable parameters stored in the memory 202. Thus,multiple versions need not be maintained for multiple engine types.

FIG. 8 is a block diagram of a vehicle with an engine system accordingto an embodiment. In this embodiment, the vehicle 240 includes an enginesystem 241 configured to provide power for the vehicle 240. The enginesystem 241 includes a controller 248 coupled to actuators 244 andsensors 246 coupled to an engine 242. The controller 248 can beconfigured to implement the various air, fuel, and spark controlsdescribed above in response to torque inputs 250 and 252 from variousother sources.

Furthermore, in an embodiment, the engine system 241 can, but need notdirectly provide locomotive power for the vehicle 240. For example, theengine system 241 can be configurable to drive an electric motor and/orgenerator.

Although a controller 248 has been described as performing the air,fuel, and spark control for an engine 242, the controller 248 can, butneed not be dedicated for such function. That is, the controller 248 canbe part of a larger engine management system, emissions control system,or the like. Furthermore, the functionality of the controller 248 can bespread across multiple devices, processors, sub-systems, or the like.

The controller 248 can be implemented in a variety of ways. For example,the controller 248 can include a general purpose processor, amicrocontroller, an application specific integrated circuit, aprogrammable logic device, a combination of such devices, or the like.

An embodiment includes a computer-readable medium storingcomputer-readable code that when executed on a computer, causes thecomputer to perform the various techniques described above. Thecomputer-readable medium can also be configured to store variousparameters described above. Thus, in an embodiment, the code can remaincommon across engine types, yet the parameters can be separatelyconfigurable and stored to create an engine-specific distribution.

Referencing FIG. 9, a controller 900 utilizing multiple torque controlschemes is depicted. The controller 900 is compatible with certain othersystem described herein, and can be utilized in whole or part in othersystems. The controller 900 is a non-limiting example, and portions ofthe controller 900 and/or certain principles utilized by the controller900 may be applicable to other systems described herein.

The description of controller 900 herein utilizes certain terms that maybe similar to terms utilized in the descriptions referencing FIGS. 1through 8. Where descriptions and utilizations of terms are notidentical, it should be understood that the terms may be utilized asdescribed in portions referencing FIGS. 1 through 8, as described in theportion referencing FIG. 9, and/or as any such terms may be understoodby one of skill in the art, except where explicitly stated otherwise.

The controller 900 includes a first torque to air model 902. The firstmodel 902 determines a limit air torque 916 in response to a long termtorque target 906, an optimal spark timing 908, and an AFR(air-fuel-ratio) lower limit value 910. The long term torque target 906is determined in response to the operating requirements of the systemhaving the controller 900, and non-limiting examples include a torquevalue requested by an operator, a torque value required to achieve adesired speed or acceleration of an engine, and/or a torque valuerequired to achieve a desired power output of an engine. The optimalspark timing is the timing desired by an overall control system, whichmay be determined for purposes of emissions, fuel economy, or otherreasons. Optimal is described in reference to the desired timing outsidethe operations of the controller 900, and may be a range of timingvalues. “Optimal” for the optimal spark timing 908 is not limited to anoptimal value for any particular consideration such as fuel economy, butsimply as defined by a system outside the controller 900.

The AFR lower limit 910 may be determined from a minimum amount of airto support the long term torque target 906, from a minimum amount of airdetermined in response to an emissions requirement, by a minimum airflow desired at a turbocharger for responsiveness, or by any otherdetermination. In certain embodiments, for example when the controller900 is operating an engine utilizing compression ignition (CI) and/orother engine where stoichiometry is not enforced (e.g. a gasoline directinjected [GDI] or stratified combustion engine) the AFR lower limit 910may be set out of the way (e.g. too low to impede the controls) and/orset to a value determined for purposes other than combustion limits. Thefirst torque to air model 902 outputs a limit air value 916.

The controller 900 further includes a second torque to air model 904.The second model 904 operates utilizing an instantaneous torque target912. The instantaneous torque target 912 is an intermediate torquetarget that is determined to be achievable in the short term by thesystem, and to bring the engine acceptably toward the long term torquetarget 906 over time. At certain operating conditions, such as but notlimited to steady state operation, the instantaneous torque target 912may be equivalent to the long term torque target 906. In certainembodiments, the instantaneous torque target 912 is determined inresponse to the limiting dynamics of an air handling system, whichgenerally responds to transient operation more slowly than fueling(timing, fuel type, and/or amount), valve timing, or spark controloperations. For example, many systems can change fuel timing and amountto a desired value quickly, and even with each individual fueling event.However, the time constant to air flow changes in response to a changein an intake valve, exhaust valve, variable geometry turbochargerposition, or other air-handling actuator can be on the order of hundredsof milliseconds or even seconds.

The second model 904 further utilizes an air target 914, which may be asuitable air flow at the long term torque target 906, an air flow valuedetermined in response to the instantaneous torque target 912, oranother target air flow value determined in the system. A maximumelement 920 provides an air command 922 consistent with the greater ofthe limit air 916 and the air value 918 determined by the second model904.

The controller 900 includes a fuel limiter 926 that trims a fuel commandin response to an output of a ratio element 924 providing the ratio ofthe air command 922 to the air target 914, and further in response to acurrent air mass 928 and an AFR limit 930. The current air mass 928 is ameasured or estimated value for the actual air flow through the engineat the execution time of the fuel limiter 926. Any known technique todetermine actual air flow is contemplated, and many techniques are knownin the art. The AFR limit 930 may be the same or a different AFR limit930 than the AFR lower limit 910, and may be determined for distinctpurposes from the AFR lower limit 910. The AFR limit 930, innon-limiting examples, is provided to ensure stoichiometric combustion,to ensure that a particulate emissions level is not exceeded, and/or toprovide for transient management ability by the controller 900 byavoiding very low air flow rates.

The fuel limiter 926 provides a pre-correction fuel command 934, whichmay be adjusted by an AFR feedback adjustment 940 control element. TheAFR feedback adjustment 940 determines a current λ value 942, which maybe estimated, calculated, and/or determined from a sensor (e.g. a wideband oxygen sensor, a NO_(x) sensor, or other sensor). The AFR feedbackadjustment 940 further determines the air target 914, and provides acorrection 944 that adjusts the pre-correction fuel command 934 to thefuel command 948. The adjustment is depicted as an additive amount inthe sum element 946. However, the fuel adjustment may be provided by anymethod, including at least by a multiplier, an enforced minimum and/ormaximum, and/or from a look-up table or more complex function. The AFRfeedback adjustment 940 ensures that the fuel command 948 will achieveproper combustion based upon the air actually present, and/or may serveother purposes in the system such as enforcing a target AFR amount foraftertreatment devices or other purposes.

The controller 900 further includes a dynamic spark adjustment 936 thatprovides a spark command 938. The dynamic spark adjustment 936determines a predicted torque 932, which is the torque value expectedfrom the fuel command 948 and the air command 922 at the current systemconditions, and/or may be the torque value expected from thepre-correction fuel command 934 and the air command 922 (as shown in theexample of FIG. 9). The dynamic spark adjustment 936 also determines theoptimal spark timing 908 and the long term torque target 906, andprovides the spark command 938. In one example, the dynamic sparkadjustment 936 provides a spark command 938 that will provide an actualtorque output of the engine that achieves the long term torque target906, and/or that is closer to the long term torque target 906 than thepredicted torque 932. The dynamic spark adjustment 936 may limit thespark command 938 to values supported by emissions determinations,and/or to values within a range of values provided by the optimal sparktiming 908.

The control architecture of the controller 900 can support torquedetermination, and fueling and air handling command determination, for aspark ignition engine, a compression ignition engine, for other enginesthat are not limited to stoichiometric operation (e.g. GDI, homogenous,or stratified combustion engines), through simple manipulation ofcalibrations within a control scheme. An example includes operating a SIengine by setting the AFR lower limit 910 and the air target 914 to thestoichiometric air value (or upper and lower limits within a range ofvalues near stoichiometric) at the target torque value, therebyoperating the engine acceptably for stoichiometric operation andcontrolling torque with the air command. An example includes opening theAFR lower limit 910 and air target 914 values for a CI engine such thatfueling is utilized to control the torque. The controller 900 furtherallows for rapid torque management utilizing spark manipulation toimprove transient control of engines managing torque control with airwhich is generally a slower responding system.

The controller 900 can be utilized to control a single engine havingmultiple fueling schemes. The controller 900 can be utilized to providea single control scheme for multiple engine families, with just acalibration difference to provide the various fueling schemes. Theutilization of a single controller 900 for multiple engine familiesprovides for manufacturing cost savings and simplification. Thecontroller 900 further supports changing of a fuel system after theengine is manufactured, for example with a conversion to another type offuel and/or support for a dual fuel system (e.g. adding natural gascapability to an engine after manufacture), where a simple calibrationupdate is much less intrusive and cheaper to implement than a computerreplacement or firmware replacement.

The schematic flow descriptions which follow provides an illustrativeembodiment of performing procedures for controlling engines withmultiple torque delivery schemes with a single controller and/or asingle implementation scheme of a controller. Operations illustrated areunderstood to be exemplary only, and operations may be combined ordivided, and added or removed, as well as re-ordered in whole or part,unless stated explicitly to the contrary herein. Certain operationsillustrated may be implemented by a computer executing a computerprogram product on a non-transient computer readable storage medium,where the computer program product comprises instructions causing thecomputer to execute one or more of the operations, or to issue commandsto other devices to execute one or more of the operations.

An operation includes providing a controller, such as any controllerdescribed herein including controller 900, and operating an engine bycontrolling torque with air at a first operating condition, andoperating the engine by controlling torque with fuel at a secondoperating condition.

An operation includes providing a controller, such as any controllerdescribed herein including controller 900, and providing a first copy ofthe controller to a first engine that controls torque with air, andproviding a second copy of the controller to a second engine thatcontrols torque with fuel.

An operation includes providing a controller, such as any controllerdescribed herein including controller 900, and operating an engine withthe controller to control torque with one of air and fuel. The operationfurther includes, at a time after the manufacture of the engine,switching the control of torque in the engine to the other one of airand fuel.

An operation includes providing a controller, such as any controllerdescribed herein including controller 900, and operating an engine witha first fuel type, and the controller controlling the torque of theengine with one of air and fuel in response to the first fuel type. Theoperation further includes performing at least one of adding a secondfuel type to the engine (e.g. as a dual fuel capable engine) and/orswitching the engine to a second fuel type, and where the controller, inresponse to the second type of fuel being utilized, controls torque bythe other of the air and fuel from the first type of fuel.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly certain exemplary embodiments have been shown and described andthat all changes and modifications that come within the spirit of theinventions are desired to be protected. It should be understood thatwhile the use of words such as preferable, preferably, preferred or morepreferred utilized in the description above indicate that the feature sodescribed may be more desirable, it nonetheless may not be necessary andembodiments lacking the same may be contemplated as within the scope ofthe invention, the scope being defined by the claims that follow. Inreading the claims, it is intended that when words such as “a,” “an,”“at least one,” or “at least one portion” are used there is no intentionto limit the claim to only one item unless specifically stated to thecontrary in the claim. When the language “at least a portion” and/or “aportion” is used the item can include a portion and/or the entire itemunless specifically stated to the contrary.

What is claimed is:
 1. A system, comprising: a memory configured tostore a parameter; a controller coupled to the memory and configured tocontrol air and fuel delivered to an engine in response to the parametersuch that the engine is controlled in a stoichiometric mode when theparameter has a first value and a lean mode when the parameter has asecond value, wherein the parameter comprises at least one air-to-fuelratio limit wherein: the at least one air-to-fuel ratio limit includesan upper air-to-fuel ratio limit and a lower air-to-fuel ratio limit;and the upper air-to-fuel ratio limit is different from the lowerair-to-fuel ratio limit in the lean mode.
 2. The system of claim 1,wherein the upper air-to-fuel ratio limit is equal to the lowerair-to-fuel ratio limit in the stoichiometric mode.
 3. A system,comprising: a memory configured to store a parameter; a controllercoupled to the memory and configured to control air and fuel deliveredto an engine in response to the parameter such that the engine iscontrolled in a stoichiometric mode when the parameter has a first valueand a lean mode when the parameter has a second value, wherein for thestoichiometric mode the parameter includes an air-to-fuel ratio lowerlimit and an air target that are set to stoichiometric air values, andfor the lean mode the parameter includes an open air-to-fuel ratio lowerlimit and air target, wherein for the lean mode the parameter furtherincludes an upper air-to-fuel ratio limit and the upper air-to-fuelratio limit is different from the open lower air-to-fuel ratio lowerlimit.
 4. The system of claim 3, wherein the controller is configured tocontrol an engine torque of the engine, wherein the controller isfurther configured to actuate an air actuator of a spark ignition enginein the stoichiometric mode to control the engine torque, and thecontroller is further configured to actuate a fuel actuator of one of acompression ignition engine and a direct gasoline injection engine inresponse to the lean mode to control the engine torque.
 5. The system ofclaim 4, wherein the controller is configured to determine a type of theengine is one of the spark ignition engine, the compression ignitionengine, and the direct gasoline injection engine and, after determiningthe type of the engine, control the engine torque by operating thecorresponding one of the air actuator in response to the stoichiometricmode and the fuel actuator in response to the lean mode.
 6. The systemof claim 5, wherein the controller is configured to switch controllingthe engine torque by operating the other of the air actuator and thefuel actuator in response to determining the type of the engine haschanged.
 7. The system of claim 5, wherein the controller is configuredto determine the type of engine in response to a fuel type.